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Big Al

6BRA

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Yes Al and Les, strong and variable winds at Diggle always inject verticals, bad enough when it's a westerly / south-westerly up the range but much worse when it's a north-easterly coming down the re-entry above and to the left of the butts (as forecast for this weekend).

Blair Atholl is also well known for this issue with some conditions (blown right = blown low too; blown left = POI left + high), but at least it is almost predictable there. I tried for many a year (in F-Class) at Diggle to compensate for this factor aiming high or low alongside the windage change as appropriate, but gave it up as a bad job in the end. For every time that I got it right, there was at least one occasion where the high/low aimed shot went exactly to the aimed elevation even though the anticipated lateral windage element had appeared. In the end, I came to the conclusion that the least bad solution was a rifle/load holding very good verticals and just worry about the windage alone, as always keeping an eye (on the plotting sheet) for elevation drift in the course of the match and allowing for that as needed.

There are obviously very strange effects at work in the Diggle Ranges valley - air movements appear to bounce around the valley sides and the sheer hillside behind the butts. Even on apparently dead still days with no mirage, rogue elevations appear - I've seen this on a couple of occasions when the range is hosting GB F-Class Association national league rounds with many of Europe's best long-range competition shooters in play at 1,000 yards - scores that one would expect to be 100 with maybe 18 or 19 V-Bulls for the top few end up as 98s and 99s with 10 to 15 V's, the dropped  points and moves out of the V usually down to elevation variations. Watching from behind the firing line and scanning along the targets with binos, this often shows as a pattern with every shot being slightly high or low as targets are pulled and marked over just two or three minutes. This leaves the shooter who has just leaked into the 4-ring at 12 o'clock say with a problem as to what to do on the subsequent shot - ignoring the poor one is usually the best course (but this isn't guaranteed).

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Yes when you aim off to compensate because of your last shots and they go where you aimed is a head banger.i had a couple of groups like that in December.cracking groups too.i am glad I've not had to shoot in wind we've had the last 2 days.

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On 1/4/2018 at 6:58 AM, No i deer said:

How was the verticles this time the Al.

Did you change anything in the load or just ran them again....?

I managed to get out today to look more closely at my load at 600yds which is the distance Im currently competing. Conditions were great with barely a breath of wind for most of the morning.

I tried six different loads, the worst having 2.6" of vertical, these were the best two loads which had 0.547" and 0.891" of vertical respectively, Im now wishing I has fired five shot groups! :(

Ive got a month before the next 600yd comp so hopefully I can get a bit more testing done but the more I shoot this little case the more Im coming to like it, I think it has great potential.

  

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Wow there stunnining groups Al.

You could head shoot rats at 600yds.

Approximately 1 inch groups at 600yds is going to bring you much glory.

It can't be a vertical issue.

I had some real bad verticals on my 6.5x47 a few months ago at 600yds.i did post about it.not sure if my barrel started speeding up or what.

The last 1000yds day in December I shot some stunning groups so I guess it was more than likely something I did that day.

With your set up the shooting isn't down to a physical shooter error.its down to your load or inconsistency in conditions.the big dog is the dogs dangles.well done Al.fruits of your labour.

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1 hour ago, No i deer said:

Wow there stunnining groups Al.

You could head shoot rats at 600yds.

Approximately 1 inch groups at 600yds is going to bring you much glory.

It can't be a vertical issue.

I had some real bad verticals on my 6.5x47 a few months ago at 600yds.i did post about it.not sure if my barrel started speeding up or what.

The last 1000yds day in December I shot some stunning groups so I guess it was more than likely something I did that day.

With your set up the shooting isn't down to a physical shooter error.its down to your load or inconsistency in conditions.the big dog is the dogs dangles.well done Al.fruits of your labour.

It was exactly that, my old load had too much vertical.

I tested 6 different loads yesterday and they showed verticals of between 2.6" and a 0.547" I could see exactly where the vertical was coming in and going out at different nodes. Conditions were perfect, zero wind. My scope has no windage on and look at how perfect they are in terms of windage alignment, sadly we dont get many days like that.

It is possible to tune out vertical as we all know but with a rifle like mine it needs to be done at long range because it doesn't show up at 100yds. Ive has single one hole groups that appeared round at 100yds that show more vertical dispersion at 600yds than horizontal on a regular basis, enough to be able to draw a conclusion.

On your second point, Ive realised shooter input is also vital in respect of how the rifle is set-up to begin with and how its shot, if its not set-up right it wont shoot to its maximum potential. Interestingly my friend who also holds a UKBRA 600yd small group record ( so clearly he can shoot) can't seem to shoot my rifle as accurately as I can when we have back to back tested. I have had to learn what this gun likes to get the best from it, its certainly not a case on dump it on the rest and expect to win like some might think. 

All that said, only the holes punched through the target in competition conditions and compared to others on the same day will tell me the full story.  

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Your verticles and horizontals sound about the thickness of your dot or reticle.having a smaller dot or finer crosshair could have you shooting even better but somehow maybe wishful thinking....!

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5 hours ago, No i deer said:

Your verticles and horizontals sound about the thickness of your dot or reticle.having a smaller dot or finer crosshair could have you shooting even better but somehow maybe wishful thinking....!

I use slightly smaller than an 1/8th MOA dot.

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No i deer, maybe you arent familaiar with the Bench Rest LR aiming options-Al confirms a 1/8 moa dot,so it's subtending under an inch and a quarter at 1000y.

BUt -within limits- size doesn't matter.Field shooters might place their dot on a crows head,or a rabbits chest,but precision LR shooters-who don't need to hit centre -and 100y BR  shooters definitely  d o NOT want bullet hole obscurion their aim point-hence their very small hole is deliberately off centre (just scope clicks)

.   The LR shooter canuse a very precise aim-essentially a figure eight with the top being the 'bull/aiming mark' (say about 4/5 inches...1/2 moa roughly) and the bottom the scope reticule dot.The two are just tangential-lightly 'kissing' eachother-the human eye is pretty good at judging this,and it's easy to repeat for all shots....so 'aim error/variation' is very small. This  can be adapted to non round aim points-eg the bottom of diamond just kiusses top of reticule dot etc-it's very precise-and because of the relatively high magnification (X30 eg) is pretty easy to see/do.YOu don't need 30x to see the bull,but to touch tangentially,you do need high mag.....

   Actually the sixe of the reticule dot could be double-its still aligned tangentially,and yo just get a fatter lowe eight shape(or small er upper eight shape,with small aim point).

Of course you 'have to see it to hit it'-but them magnification iss not just to see the aimpoint-it's to help this very fine judged 'just touch' figure eight.

   Cross hairs adapt to-bottom of bull is tangential to horizontal cross hair,and middle on vertical-again slim cross hair helpsfine precision-a telegraph pole does not!

   There are all sorts of reasons BR tends to produce better group results-but it's also how the equipment is used . A reticule dot larger than the aim dot won't aid precision bullet placement,if it's just superimposed 'field style'-you don't know if it's centered-and that really matters when shooting for groups that are well under 3 moa.Remember 1/4  aim error  error is 2.5 inches just on its own....

 

gbal

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Hi George.

I didn' realise the figure 8 was used.its not something that I had thought of or was told but I do understand the theory.when I ammo test I usually have poi high of centre not to ruin the aiming point depending on where the first shot goes.sometimes I will finish the group if it's too close to poa. atb No I deer ;)

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I would like to see some 1000yds 5 shot ammo testing groups with the BRA B)

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You will - on 25th March.  The day of our first 1000 yd BR shoot.  But, we may have our electronic target up and running before then - which would be ideal for a bit of testing.

Generally, testing at 300 yards is OK.  If you test at 1000 yds there are too many other influences.  If you can shoot around an inch at 300yds it's generally competitive at 1000 yds.

 

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I would be disappointed if my loads didn't shoot inside 1 inch at 300yds but they may not.i would be more surprised if they didnt not that I test them at 300yds.with your SEB rests etc that  should be fairly easy....?

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Hmmmm.......don't equate  hi tech/spec equipment with the skill needed to use it to good effect- for example,a SEB rest does absolutely nothing to give a wind solution,though it does contribute to an excellent launch platform when that solution has been decided (of course 'inside an inch for 5 shots' would be more difficult off a wobbly  sand filled old sock,alone,with the same wind solution).    :-)

Top spec rig/gear is maybe neccessary,but not in itself sufficient,for record approaching holes on paper.

gbal

 

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4 hours ago, No i deer said:

I would be disappointed if my loads didn't shoot inside 1 inch at 300yds but they may not.i would be more surprised if they didnt not that I test them at 300yds.with your SEB rests etc that  should be fairly easy....?

 

".......... inside an inch at 300yds" which we'll take as the absolute maximum to achieve that (0.99") equates to 0.315-MOA for the centre to centre dispersion. (MOA here is the key unit - as in all ballistics calculations.)

So, one assumes that as you've not actually shot any sub one-inch groups at this distance that you're looking for 0.33-inch groups at 100 yard groups, still 0.315-MOA. Easey-peasey, we can all shoot just under third of an inch groups at 100 (now what's that common shooting forum phrase? ah, yes .........) all day long.

Actually, consistently shooting groups that average 0.33" at 100, isn't as easy as many believe. ........ and we're talking five round groups. If we're shooting 3-round 0.33" groups, statistical analysis says that you have to multiply the group size by 1.28 to get the equivalent value for five shots, reducing that 0.33" to 0.27" if it's only a threesome.

BUT .......... shooting a 0.315-MOA group at 100, or 300, yards doesn't equate to the  same performance in MOA at other distances. Dispersion tends to change in a true linear manner according to distance in identical external conditions. The amount has been calculated as being 0.023-MOA per 100 yards change in the shooting distance.  So, to achieve the equivalent of shooting 0.99" at 300 (0.315-MOA), one has to achieve 0.315 minus 0.046 = 0.269-MOA at 100. 0.269-MOA = 0.281 inches at 100, doable with a very high quality rifle / ammunition combination but actually getting pretty hard to achieve serially averaging several groups. It's marginally better than many top F-Class shooters actually achieve with their custom kit in load development.

The Gun Pimp says that under an inch at 300 is 'usually competitive' at 1,000. Using the 0.023-MOA / 100 yards formula, we get 0.315 + (7 X 0.023) = 0.476-MOA at 1,000. As 1,000 yards is 10.46-MOA, actual estimated group size is therefore 0.476 X 10.46 = 4.98 inches centre to centre, or just under 5 inches. And that's certainly where starting to be competitive comes in - the number of sub 5-inch groups shot over the UKBRA 6-match 1,000 yard annual series at Diggle is actually rather small.

However, that just under 5-inches  figure is without the effect of the notorious Diggle wind changes, not to mention the occasional bit of mirage upsetting aiming, not to mention small amounts of barrel heat produced mirage that can inject vertical even without the shooter seeing a visible mirage through the scope. That's why there aren't that many sub 5-inch groups shot there, so the 'under an inch at 300' is just a useful rule of thumb to know you have something that mechanically might be competitive, but shooter skill, experience and let's be honest luck too come into the equation, not to mention what Atlantic weather systems give you on the day. On some days, anything significantly under 10-inches is good.

Mentioning luck, plain old luck is a factor, BUT luck never, ever runs over the course of shooting four groups - I know that from bitter experience!!)

So where do these various factors I've quoted come from? Modern Advancements in Long range Shooting Volume II by Bryan LItz and they are based on analysis of very large numbers of groups fired in competition on US ranges as well as Applied Ballistics LLC's own range tests. As Bryan Litz explains there is no such thing as 100% consistently balanced and identical bullets short of machining each and every example to CNC machine standards from very high grade billets - and the greater the distance, the greater the small but significant inbuilt dispersion even with the best of today's off the shelf match bullets. 

 

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Excellent post Laurie.

I will read it again until I've grasped it all.yes my 284 has proved is capable of very small groups if I do my bit but i cant always do it as been said it cannot be done all day long.not being familiar with these SEB type rest though I did get behind a rifle on stickledown in this type set up and it was remarkably steady.i am 100 percent sure my grouping consistency would much better when ammo testing or competing using them.after all these rests were designed  enhance the shooters precision.the rifles you f classers and br shooters use are also designed for the purpose too with absalute stabilty in mind with the wide flat forends and the butts of the rifles are designed to run on the rear bags.i can see the attraction to this type of shooting though it's different to the type of shooting I do.i will take all the luck I can :P

Hi George.

I would bother to test ammo at 300yds if it was windy.i would wait for a nice day mate.

This has been a great thread B)

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1 hour ago, No i deer said:

i can see the attraction to this type of shooting though it's different to the type of shooting I do.:P

"It's all about competition - last week I was shooting in an F Class Comp.  This Sunday it'll be a McQueen comp. and next week F Class at 900 yards, then Tactical then Benchrest at 600 yards.  As long as it's a comp. I'll shoot it."

I would bother to test ammo at 300yds if it was windy.i would wait for a nice day mate.

"Unfortunately, we don't get 'nice days' at Diggle - the MPH wind speed is rarely in single figures but you can still load test".

 B)

 

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I like the competition too..!

Do you shoot McQueens without a rear bag Vince...?

I wish I lived near a range like Diggle.i could do all the load development and shooting I want.i could really get to see what my rifles and myself are capable of.ive put many a nice shot down stickledown,century and short siberia in our club comps.most of my load testing is done off the roof of my pickup across the fields.when its breezy/windy it shakes my pickup making it that much harder to hold still.ive not got the luxury of covered firing points and concrete benches.i wish I did...!

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Yes - we are very lucky with Diggle - as more and more shooters are beginning to realise. We don't get 'perfect' days but without the wind - where's the challenge?

Rear bag/mono-pod not permitted in Diggle McQueen.

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Competition,plinking,etc...fine...it's a hobby,and one which most can enjoy greatly without an indepth understanding of internal and external ballistics.But these have some effect,and not always small,even if some are negligible for the 'hobby' shooter,not focussed on world championships.

   ITmay be helpful to think of some distinctions:

1) The (intrinsic) precision of the rig and ammunition- essentially,how the rifle/ammo group under perfect conditions (this is largely an engineering-ammo too- and quality control issue). Laurie's timely reminder of Litz point-there are no perfectly cloned boxes of bullets,in  the finest analysis (not even something as simple as length in many!)

2)The accuracy the shooter imposes-ie making shooting solutions (especially wind) to centrethe shots on the 'bull' (heart,tin can-what the shooter wants to hit).Since some,but not all,of the factors are indeterminate (wind from muzzle to target-cannot be measured and allowed for with precision) there is a skill factor (wind reading) quite separate from deteminate factors (Coreolis and the like) that a good ballistics solver program can apply.There is also the  more traditional,basic 'good shooting' technique...which interacrts with...

3) technical sophistication in the auxiliary equipment used- Big Al's 50 lb rig will be pretty stable in a Seb quality front rest,and a 2 oz trigger won't move it much when caressed by the trigger finger; a quality scope will minimise sighting errors (both optically and mechanically-a click will be a click,reliably); good stock fit;a very stable table (BR concrete will remove almost all  sources of unwanted movement of the rig/rest;). and so on...

Group shooting ( and much BR) demands very high precision,mainly (in the limit that's 'rail guns'- virtually no shooter contact.)

Score shooting (Fclass eg) demands both precision and accuracy (shots in the small bull/X bull),not just close together somewhere on paper.

Stalking and varminting demand accuracy-most especially from the first,and probably ,only shot (though such consistency really assumes quite good precision too-if several shots are taken).

OK,what matters are the underlying concepts-what the rifle/ammo can do,what the shooter can do,and what the auxiliary equipment can do to minimise shot dispersion in the first two.

And yes, 'you know all this,in some sense?'-hmmm... well,they get confused all too often,as do attempts to improve overall results-the best progress is made by considering where the 'weakest link' is located.....a super scope won't improve wind reading by itself-skill cannot be bought 'off the shelf',or made to order by a top 'smith-though the rig can.

Understanding these fundamentals allows a sensible use of resources to improve performance.Some can actually be 'quantified'-or at least the points of diminishing returns on investment specified (splitting kernels may be 'splitting hairs'-we shall see),but if your rifle's intrinsic 5 shot precision is 1.5 moa,and you can't read wind changes to 2 mph at 1000y,then finessing MVSD to a single low digit,might not lead to radical improvements on it's own.

"Necessary,but not sufficient' should be a central consideration (always interpreted within the parameters of what is 'aimed' for in performance terms;targets and hit zones vary in size).

For much of all this,modern analyses allow a simple quantitative summary to be calculated...( "improving moa precision by .5,will improve hit rate on 6" gongs at 700y by 42 %"-that sort of detail).

That may be more informative  than  'I can usually get 3 shots  under an inch,on a good day,when I do my bit".

Or not-it's a hobby!!  - but the choice is there.

gbal

 

 

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2 hours ago, The Gun Pimp said:

Yes - we are very lucky with Diggle - as more and more shoo:Dters are beginning to realise. We don't get 'perfect' days but without the wind - where's the challenge?

Rear bag/mono-pod not permitted in Diggle McQueen.

As it should be.no bag or monopod :D

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2 hours ago, The Gun Pimp said:

Yes - we are very lucky with Diggle - as more and more shooters are beginning to realise.

We don't get 'perfect' days but without the wind - where's the challenge?

 

World records! ;)

Something you said to me Vince on my first truly windy comp, its always about shooting smaller groups then everyone else. That point would always remain regardless so if you could arrange a few truly still days I would be most grateful :)

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On 1/9/2018 at 9:10 AM, No i deer said:

I would like to see some 1000yds 5 shot ammo testing groups with the BRA B)

I expect the BRA to be competitive at 1000yds, it has already set world records in the US at that distance.

Essentially its firing the same 105 class bullets as the Dasher at one of the same accuracy nodes around 2970fps, Ive already won with the 6 Dasher a few times so God willing it should be competitive.

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As dasher brass is off the shelf now I may try that instead of the 6mm br..

I will weigh up the differences and make my choice.both have already a proven track record and don't really wanna do any unnecessary fire forming.i don' need too as I don't compete like you gents do but I would like too.i do still want my choice as accurate as possible.i fancy one of them little seb rests Laurie tested and see if I get more consistant.

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